Segment and Related Information, by Product (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 31, 2013	Sep. 29, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue from External Customer [Line Items]
Net sales	$ 516.0	$ 543.5	$ 421.1	$ 244.4	$ 256.8	$ 254.2	$ 256.8	$ 250.4	$ 1,725.0	$ 1,018.2	$ 996.8
Paper PCC [Member]
Revenue from External Customer [Line Items]
Net sales									454.5	480.0	471.0
Specialty PCC [Member]
Revenue from External Customer [Line Items]
Net sales									66.1	67.2	65.9
Talc [Member]
Revenue from External Customer [Line Items]
Net sales									55.5	50.9	48.1
GCC [Member]
Revenue from External Customer [Line Items]
Net sales									74.0	71.7	67.9
Refractory Products [Member]
Revenue from External Customer [Line Items]
Net sales									273.9	264.0	264.1
Metallurgical Products [Member]
Revenue from External Customer [Line Items]
Net sales									85.8	84.4	79.3
Metalcasting [Member]
Revenue from External Customer [Line Items]
Net sales									181.4	0	0
Household, Personal Care and Specialty Products [Member]
Revenue from External Customer [Line Items]
Net sales									108.0	0	0
Basic Minerals and Other Products [Member]
Revenue from External Customer [Line Items]
Net sales									63.4	0	0
Environmental Products [Member]
Revenue from External Customer [Line Items]
Net sales									70.7	0	0
Building Materials and Other Products [Member]
Revenue from External Customer [Line Items]
Net sales									81.6	0	0
Energy Services [Member]
Revenue from External Customer [Line Items]
Net sales									$ 210.1	$ 0	$ 0